This invention relates to a fluid bearing installed between rotating and stationary axle components that accommodates both radial and thrust loads.
Vehicle drive axle assemblies include various bearing components that provide rotational support for components that rotate within the axle assembly. An example of one application is the use of bearings in a wheel end assembly. A vehicle hub is mounted for rotation about a wheel spindle. The vehicle tire and rim are mounted to the hub. As the hub rotates, the tire rotates which reacts against the ground to move the vehicle in the desired direction. A pair of wheel bearings is mounted between the hub and the spindle to provide rotational support for the wheel hub on the spindle.
Typically, these wheel bearings are tapered roller bearings that accommodate radial loading and thrust loading from one direction. A pair of wheel bearings is required to provide sufficient radial loading support and to accommodate thrust loading from opposing directions. One tapered wheel bearing is mounted in first position to accommodate thrust load from one direction while the other tapered wheel bearing is mounted in a second position to accommodate thrust load from an opposing direction.
One disadvantage with tapered roller bearings is that they are subject to fatigue and wear. If one of the bearings fails further damage to other wheel end components can occur resulting in extensive repairs and downtime. Another disadvantage is that roller bearings are noisy. Additionally, roller bearings are expensive and difficult to install and set to proper pre-load conditions.
Thus, it is desirable to have a simplified bearing that can be used in various bearing applications within a drive axle assembly and that can accommodate radial loading as well as thrust loading from opposing directions. The bearing should also provide quiet operation, be easy to install, and provide minimal efficiency loss.
In a disclosed embodiment of this invention, a drive axle assembly includes a stationary member and a rotating member spaced apart from the stationary member to form a gap. A fluid is received within the gap to create a bearing surface between the stationary and rotating members. The fluid provides sufficient pressure to rotatably support the rotating member with respect to the stationary member. Thus, a fluid bearing is provided between the stationary and rotating members that can accommodate radial and thrust loading from multiple directions.
In one disclosed embodiment, the stationary member includes a groove and the rotating member includes a protruding rib. The rib is received within the groove. The rib includes a first surface for accommodating radial loads, a second surface for accommodating thrust loads from one direction, and a third surface for accommodating thrust loads from an opposing direction. The fluid filled gap is formed between the rib and the groove and extends along the lengths of the stationary and rotating members.
A preferred method for supporting a rotating member on a stationary member in a vehicle drive axle includes the following steps. The rotating member is spaced apart from the stationary member to form a gap. The gap is filled with a fluid. The fluid is sealed within the gap to form a pressurized fluid bearing between the stationary and rotating members such that the fluid bearing provides load support as the rotating member rotates with respect to the stationary member. Additional steps include forming a groove on one of the stationary or rotating members and a rib on the other of the stationary or rotating members and aligning the rib within the groove.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.